The present invention relates to the sector of household accessories and in particular concerns a locking device for the various elements of telescopic rods. Said telescopic units can be used to support brooms, flags, clothes-stands, hooks, curtains and any other object that can be manually moved and supported. In order to simplify the description, the application regarding brooms will be described here below, though this is not to be intended as a limitation. In fact, brooms are known, the handle of which is divided in two or more sliding telescopic tubes positioned one inside the other.
Obviously, it is necessary to adopt a system to lock the two tubes, so that the tubes cannot slide reciprocally and that the length of the broom can be adjusted according to the need.
These brooms are particularly practical to clean either floors and ceilings, even if very high, and walls, too. However, there are some problems with the assembly of such tubes one inside the other and with locking them. At present an external metal ring is used to tighten the two tubes reciprocally. Such metal ring screws on a threaded head of the outer tube, which is provided with slits, thus narrowing it and obtaining the locking on the inner tube. Such devices are expensive and not aesthetical in appearence.
At present also expansion elements are used, which comprise a cylindrical body with an internal, truncated cone-shaped thread on one side, while the other side is half closed and provided with one or more slits to facilitate the expansion of the element itself.
A separating device, integral with the inner tube, is inserted into the expansion element, which can slide in the outer tube. Such a separating device comprises a truncated cone-shaped point provided with a thread, which screws inside the expansion element, thus widening it and making it exert a certain pressure on the inner walls of the outer tube. In this way, through the rotation of the inner and outer tube in opposite directions, it is possible to obtain the screwing of the separating device on the expansion element, with consequent locking of the two tubes.
This system can obviously be applied to two or more telescopic tubes. The drawback of this system is that it is mono-directional and that it makes it necessary to decide during the assembly phase in which direction the tightening element made up by the expander must be installed. This system may lead to mistakes in the assembly, which make it necessary to put aside the rods assembled incorrectly, to disassemble them in order to reverse the expander and to reassemble the unit.
At the moment, these inconveniences can be avoided only by proceeding very slowly and carefully.